FELLWOLVES! power of the pack
by Glassplant
Summary: Two worlds collide when the Fellwolf brothers end up in Underswap after they are kicked out of their pack. Can the Underswap brothers and their friends help these two dimentional brothers ajust to a world with different rules to their own? we'll just have to wait and see.
1. Chapter 1: the Disappearance

A howl was heard threw out the icy cavern where Snowdin lay among the forests of evergreens. Many a monster watched as a wolf skeleton hybrid type creature ran threw town towards the deep forest where the ruins, the place where monster kind's civilization underground began, lay.

Almost all the town knew about this large wolf skeleton, son of the former pack leader that had lived in this cavern since near the beginning. The former pack leader, W.D. Gaster, and his wife, Berlin, had been changed by an experiment that Gaster, the former royal scientist, had been working on before they were forced underground by the humans. The disaster of an experiment had turned the only two well known skeletons in the underground into half wolf creatures. The two's lower arms, hands, lower legs, and feet turned into the the paws and lower legs of a wolf. They gained wolf ears on their skulls and grew wolf tails as long as their arms. Though the couple sadly lost the ability to speak in the human's English Gaster was still able to communicate with the rest of monster kind thanks to the fact he often spoke with hand symbols.

As time had went on and the underground had changed into a place where you had to fight to survive Gaster and his wife had moved to the Snowdin cavern where Gaster became a sentry and used his pay to live a life with his family and work deep in the woods away from the town of Snowdin. Till one day Gaster and his wife disappeared.

It wasn't till a little over a year later that the family was seen again with the addition of five children, two girls and three boys, though only one of those children and, as far as the vilage knew, the only member of the Gaster family survives to today thanks to the pack that invaded the Gaster family's teritory five or six months ago. So the town watched as Gasters eldest son of the quintuplets, Papyrus, ran to the forest out of their line of sight never knowing the truth of what Papyrus was running to.

Papyrus ran through Snowdin forest as he heard the howl slice threw the air, there was only one person he knew who could make that sound, but what made matters much worse is what type of howl it was. A distress call from the only person he had left in his family, his baby brother.

The clearing in front of the cave Papyrus and his baby brother had been forced to live in after Greatest dog and his pack invaded and took over his family's territory had three or four of Greatest dogs pups crowded around a skeleton wolf hybrid creature that was only about half the size of Greatest dog's pups. Papyrus quickly sprung into the clearing growling at the pups as his brother ran over to him and hid under him. Greater dog's pups growled at him and tried to get at his baby brother. While in any other circumstances if other pups decided to play with his baby brother then it would be an amazing thing, but not with Greatest dog's pups. These pups, like their father, despised his baby brother so much that they bullied his baby brother. Hurting him just because they could. Papyrus wouldn't stand for this so with speed and precision that came from years of training and practice in hunting pray he scared away the pups who quickly ran off to their mother or mothers, dependent on how loyal Greatest dog is to his mate, leaving the two brothers alone.

Papyrus looked down at his little brother who sat there gripping his leg as he tried to hide from the world that seemed to despise and torture him every step of the way. A quick nuzzle though got his brother off his leg and allowed Papyrus to get a better look at the young skeleton wolf. Though his brother didn't look like he had gotten any new bruises or fractures to add to his growing collection of injuries the old ones were still clearly visible in the areas his tattered and torn jacket and shorts couldn't cover.

A growl though from the young pups stomach pulled Papyrus out of his musing as his brother gives a whimper of pain. The elder skeleton wolf gained a sad look at seeing his brother in so much pain before leading his brother back into their barren cave were, unlike their original cave, there was nothing to protect them from the freezing air of the frozen caver or to lay comfortably on to do what he had to do. So without much prompt Papyrus got his brother to lay down at his side an he placed his head against his brother's and transferred as much magic as he could into the small body beside him hoping that it might curb the hunger pains that his brother had been experiencing all of his life so far.

After a bit of time Papyrus stopped giving his brother magic before noticing that his baby brother had fallen asleep in the mists of the transfer. A quick look outside proved why as well, it was what the underground distinguished as night. So Papyrus curled around his brother and fell asleep.

By the next morning Papyrus found himself curled around his younger brother as the pup slept against his side half hidden by his tail. He looked sadly at his brother, smaller then all the other pups in their pack, a runt in all sense of the word. It didn't help that the their mother had died minutes after giving birth to Sans and his two siblings, who had died minutes later, leaving Sans without the milk he needed to grow, since none of the other mothers in their pack would spare any milk for his lone sibling. Leaving him, Papyrus, to keep his remaining brother alive with his own magic as nutrients and to protect him from from the pack that wanted the waist of resources and space dead.

After a few minutes Papyrus was pulled out of his musing by the barking of Greatest dog telling him to go patrol the territory. Papyrus growled at Greatest dog to go do it himself and that he needed to take care of and feed his baby brother. Greatest dog replied with a bark saying not to worry about his brother and that he and the pack would take care of sans.

This surprised Papyrus seeing as the pack hated his baby brother but he did not look a gifted hoarse in the mouth and barked out a fine before slowly getting up and exiting the cave leaving sans in there. As he exited the cave he stared at Greatest dog in the eyes, even if Greatest dog was an inch or two taller before running of on all fours to do as he was told.

Sans slept through his brother getting up but he did wake up as he felt someone pick him up by the hood of his jacket. His eyes shot open and he quickly looked up to see one of the females in Greatest dog's pack carry him out of his den before dropping him unceremoniously in the center of the clearing outside the den, right in the middle of a circle consisting of Greatest dog's pack. A whimper escaped Sans lips as the dogs grew closer to before Greatest dog started to bark at him about how useless and small he was and how his sons were so much better then him.

Sans looked down at his paws at this, he had listened to this verbal abuse all of his known life so far and no matter how much his brother told him he wasn't a burden to him and the pack he was positive he was just a waste of dust. The next bark from Greatest pulled him out of his loathing though, a bark that said that since he had no good use that the only thing he would be good for was EXP. Sans' stared at the large dog in shock before releasing a whimper and watched all the dogs in the circle creep closer.

In that second only one thing passed through Sans' mind as the dogs bearing there teeth drew closer, he didn't want to die. So with magic he he didn't have any control over he pushed it to do anything to keep him alive and with a bright flash he found himself no longer in the middle of the dog pack circle but right outside it. A quick look back showed him how all the pack were currently disoriented by the sudden flash of light. Sans used this to his advantage and started running on his shaky legs.

Sans didn't get very far, half a mile at most, with the minute or so head start before hearing the pack give a howl that his brother had taught him the meaning of, the call of the hunt. A shiver ran up his spine as he heard the call because there was only one thing they could currently be hunting for and that was him. Sans kept running using his small stature as well as his anatomy to his advantage for once to get through small gaps between trees and to get through thorn bush patches that his pursuers would have go around or risk hurting themselves.

Yet even with all these delays Sans found that his pursuers were still after him and getting closer. He started to panic as he realized he was all out of tricks to get them off his back before being stopped by the one last things he wanted to be stopped by, the cavern wall. Fear exploded in his soul as he realized their was no were else to go, no escape.

That is till a light came into existence a few feet away from him. Sans stared at the light in aw as it displayed a place his brother had only ever told him about, Snowdin town. He quickly realized that this must be one of the shortcuts his brother had told him about that their father had discovered years before he was born. Sans was quickly pulled out of his aw though as he heard the howl of the hunt only a few meters away from him. Panic pulsed threw Sans for a moment before he quickly ran over to the portal hoping beyond hope that whatever lay on the other side of the shortcut was better then here before he jumped through the shortcut.

After Sans jumped through the "shortcut" it closed behind him leaving no indication it was ever there. Leaving the pack of dogs to growl in anger at the fact that their pray escaped.


	2. Chapter 2: Wolf in Snowdin

... well this is turning out well people like it so I will keep going. though I have to mention I did not come up with the idea of the fell wolf brothers. that would be a tumbler user by the name of Sanspar. go check him out if you want... naughtier stuff then my story.

either way, on with the show.

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Sans ran around the kitchen in his and his brothers home on the edge of Snowdin collecting the materials he needed to make his amazing tacos for breakfast. Humming escaped his lips as he got to work on cooking the onions and mushrooms for the tacos. When Sans finished making the tacos he walked into the living room and yelled up the stairs "PAPYRUS! IT'S TIME FOR BREAKFAST! GET YOUR LAZY BUT UP ALREADY!"

From upstairs sans heard a groan before the door to his brother's room opens revealing Papyrus in just his tank top and cargo shorts looking to be half asleep still as he walked down stairs saying with a yawn "yeah, yeah bro, I'm coming."

Sans gave smile as his brother reached the bottom of the stairs and quickly mad his way over garbing his brother's bare bone hand with his gloved one leading him towards the kitchen, that is till the doorbell range. Both brothers looked at the door in surprise, no one came to their home at this hour of the morning usually unless something was seriously wrong. Sans quickly let go his brother's hand and went to answer over to the door and answered it to find Dogamy at the door, breathing heavy, without his wife. The fact that Dogany was without his wife was a huge surprise and left Sans extremely nerves seeing as the two only left each others side once when Dogaressa and the rest of the dog pack, except for Dogany, had gotten trapped in a side cavern after the entrance had caved in. Sans desperately hoped it wasn't anything like that again, they had barely been able to get all of the pack out of the side cave before it had collapsed in on it's self.

"DOGANY? WHAT'S WRONG? DID SOMETHING HAPPEN?" Sans said looked Dogany over, he didn't look hurt so that was at least a good sign.

The fact that Dogany was at the door quickly caught Papyrus' attention as he made his way over as Dogany tried to gain back his breathing for a moment before Dogany says "there's a wolf or something like that running around town causing disasters. The guard has been trying to catch it but it keeps running away from us, we don't know what to do."

Sans and Papyrus looked at Dogamy in confusion, a wolf? What was a wolf doing in the underground, much less Snowdin town? The two brothers then looked at each other before Papyrus says "we'll be out in a few minutes to help Dogamy."

At this Dogamy nods before running off as Papyrus heads upstairs to grab his orange hoodie and shoes so that the two brothers can go help.

Sans ran around the town called Snowdin trying to escape the dog pack. He hadn't expected the dog pack to be in town so the minute he saw them he started running. He had knocked over some things in his rush to escape, small movable caves filled with horrible smelling things, stacks of branches, and even one of two small tree that had been folding back an avalanche.

Sans quickly dodged the large dog with a bone in his mouth causing him to crash into a tree cave creating a new opening letting new star light seep into the cavern. He heard him howl something in a strange tong that he couldn't deduce the meaning of. Another dog with a sharp circular stone attached to their back jumped out in front of him reaching for him with their paws to pin him down, so with a quick move he slid under the dog leaving them to crash into the big lumbering dog that him chasing him from behind knocking both to the ground.

Sans jumped up onto one of the closed small caves and used it to get onto the cliffs of the tree caves to gain some higher ground to escape the dog pack. Suddenly in the gap between two of the tree caves a dog head appeared scaring him and causing him to run the other way until he ran out of tree caves to run on leaving him on the the edge trapped on high ground with the tree line being a good few few feet away. Sans quickly looked down to see the pack circling the tree cave as a whimper escaped his lips as he realized he was trapped up on the cliffs with no way down unless he backtracked which would get him caught.

Dogamy returned to the group of dog guards to find all of them much worse for wear then when he left them. Only one question came to Dagany's mind as he stared at his group "what in Toriel's name happened!?"

Dogaressa, Dogamy's wife, was the one to answer with a "the little wolf was faster then we thought."

"i'll say!" Doggo said as he lit himself a new bone to calm his nerves and to dull down the sting of the bruises and cuts he had gained when he crashed into and through a wall of a house trying to grab the wolf "that wolf is fast, I couldn't even keep up with them."

Greater dog even gave a whine of agreement as he tried to pull Dogaressa's ax out of his armor. It was then that the two skeleton brothers finally found the dogs with Papyrus trying to catch his breath since he had been forced to run after his brother who had started running to find the dogs the minute they exited their house. Sans on the other hand was looking around trying to spot the wolf the dogs said they had been chasing before asking "where is the wolf?"

All the dogs pointed up and said in unison "on the roof."

Both brothers looked up at the roof before Papyrus says in confusion "how in Toriel's name did it get up there?"

Sans on the other hand was more focused on the task at hand and quickly voiced it. "PAPPY, THAT ISN'T IMPORTANT RIGHT NOW! WE NEED TO CAPTURE THE WOLF NOW BEFORE IT GATS AWAY AGAIN AND CAUSES MORE HAVOC!"

"Right," Papyrus says as he continues looking up at the roof "but how in Toriel's name are we suppose to get up there to do that?"

Sans gives a smile before laughing and saying "THE MAGNIFICENT SANS WILL USE HIS TO MAGIC TO GET ON TOP OF THE HOME!"

Papyrus frown a bit before saying in concern "You sure bro?"

"OF COURSE PAPPY! IT'S COMPLETELY SAFE!" Sans says as he summons a platform of bones and steps onto it before it starts to float up the the edge of the roof.

Once the platform reached the edge of the roof Sans stepped off and let the magic he was using to create the platform dissipate. Once he was sure that his magic had returned to him Sans looked around the roof for the wolf, what he found though wasn't a wolf.

Huddled next to the house's chimney was a skeleton creature that looked a lot like him if he was a baby bones, but instead of his normal hands and feet there were paws as well as wolf ears and a tail on the creature. The creature also seemed to be wearing cloths, which consisted of just a jacket and a pair of shorts, that were worn and torn in so many places that it looked like they were just hanging on by a thread. Under the cloths though is something that almost breaks Sans' heart, scars. "oh you poor thing." Sans says as quietly as he can before slowly creeping up to the skeletal creature.

"hey their little buddy it's okay." Sans says as he moves to place his hand on the pup's head,but the creature backs up trying to get away from the unknown hand.

"don't worry little guy, I'm not going to hurt you." Sans says as he he holds his hand out to the pup after realizing how scared they were of him.

The pup stayed out of Sans' reach for a good long while just looking at him for a bit before looking at his hand and slowly walks over. The wolf skeleton sniffs Sans' hand before rubbing his head against Sans' hand. Sans smiles at this before cautiously petting the pups head and saying quietly "see, I didn't hurt you."

"now," Sans says as he pick up the pup "lets get you down off this roof and somewhere safe and warm."

Sans didn't understand what the skeleton was saying but it sounded soothing to him as well as familiar. Reminding him so much of his brother who he may never see again. Even the smell on this skeleton was very similar though it made him miss his brother. Sans pulled his thought away from this though as the armor clad skeleton walked with him in his arms to the edge of the tree cave. Sans watched in fascination as the skeleton make a gesture with one of his hands that caused bones to come into existence right at the edge of the roof.

Sans had never seen magic like this before. Sure his brother used magic on occasions, though most of his brother's magic was given to him to keep him alive, but it was never anything like this it was mostly just gravity manipulation to decrease the amount of friction he had deal with to go faster, though he had mentioned having a "special attack". This thought quickly leaves Sans head though as the platform starts to lower to the cavern floor where the dog pack was.

Sans flinched as the nails of the wolf skeleton creature pushed themselves into his bones as they descended to the ground to were his brother and the dogs sat waiting for him, chipping a bit of his large amount of HP. "sh..." he whispers as he rubs the pups back hoping to calm the pup down. "it's okay buddy. I won't let any of them hurt you."

The pup seems to calm down as they hear this, and within seconds the two are on the ground with the dogs and Papyrus. Papyrus quickly comes over and checks Sans over while also looking at the wolf creature in his arms. "Happy your okay bro," Papyrus says as he finds his brother free for the most part of injury "but what in Toriel's name is this thing?"

Sans quickly smiles and says "THIS LITTLE GUY IS WHAT THE DOGANY AND HIS FRIENDS THOUGHT WAS A WOLF."

"huh..." Papyrus says as looks over the wolf skeleton creature. "i can see why they made that mistake."

Sans then looks Papyrus in the eyes with his eyes having stars in them before asking "CAN WE KEEP HIM!?"

Papyrus stops everything he is doing in shock before saying "Sans that's a big responsibility, plus for all we know this little guy has a family he needs to return to."

Sans smiles before saying "I KNOW AND THAT'S WHY WE NEED TO KEEP HIM FOR NOW! WE NEED TO KEEP HIS SAFE TILL WE FIND HIS FAMILY."

Papyrus sighs before saying "your not going to let this go are you."

"NOPE!" Sans says with a smile as starts to carries the pup with him towards his house leaving Papyrus and the dog guard standing there.

"well..." Papyrus says as he watches his brother walk off. "I guess that's settled." before running after his brother leaving the dogs their in confusion.

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well, that was fun. hope you guys enjoy and please tell me what you think in the comments bellow.


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